1. Field of the Invention
The present invention relates generally to Digital Rights Management (DRM), and more particularly, to a method and apparatus for providing a DRM service in a user terminal regardless of the type of a DRM system.
2. Description of the Related Art
DRM service is technology for continuously managing and protecting intellectual property rights of digital content using encryption technology for securely delivering a variety of content from a content provider to a user and preventing the user from illegally distributing the received content. DRM technology protects information throughout the entire life cycle of digital content from creation to distribution, use and disposal thereof, and may protect user rights not only in the online environment but also in the offline environment.
In order to use content to which DRM technology is applied (“DRM content”) on a client device, the client device should first access a system providing the DRM content and download the DRM content, metadata for the DRM content, and a license. The metadata is data in which information about the DRM content is stored, and the license is data specifying an encryption key used to decrypt encrypted DRM content and access rights (for example, the number of accesses, period, etc.) to the DRM content. After the DRM content and the license are completely downloaded through this process, the client device allows the user to use the DRM content. Therefore, in order for the user to use DRM content, a DRM agent capable of executing a DRM solution should be implemented in the client device.
Presently, there are many different types of DRM systems on the market, such as an Open Mobile Alliance (OMA) DRM system, a Marlin DRM system, and a Widevine DRM system are available. These DRM systems are similar in terms of encrypting digital content before its delivery and granting access rights to the digital content, i.e., in terms of using a license, but they are different in the language or format expressing the license, and also different in the format of a message used for execution of the DRM service. Therefore, when the DRM system used by a content provider is different from the DRM system supported by the client device, incompatibility issues arise.
Accordingly, multiple DRM systems are applied to a license for DRM content, and information about the multiple DRM systems is provided together with the DRM content provided to the client device. The client device acquires a license based on information about a DRM system corresponding to a DRM agent installed therein among the multiple DRM systems, and runs the DRM content.
Problems arise when a client device has no DRM agent installed or does not support a DRM system applied to the content. Therefore, a method for using DRM content in such situations is required. That is, when DRM content is provided to a client device, information about a DRM system applied to digital content and information on a DRM module are downloaded, and provided together to the client device, and based on the information, the client device may download the DRM module and then use the DRM content.
Currently, however, a DRM download mechanism may not be handled through the file format used for providing DRM content. For example, Protected Interoperable File Format (PIFF) is the latest file format for signaling, which may be used when multiple DRM systems are applied to DRM content. When DRM content is delivered using a PIFF file, it may be assumed that one or more DRM systems are applied to DRM content. However, a client device may support none of the multiple DRM systems in which case the client device will not be able to use the DRM content because information about the multiple DRM systems is only included in the PIFF file.
Accordingly, there is a need to support DRM protection signaling that may be downloaded using the popular file formats.